Measuring apparatus of sliding friction coefficient for vehicle running road surface

ABSTRACT

A measuring apparatus of sliding friction coefficient for vehicle running road surface includes a measuring wheel ( 4 ) supported rotatably on a support frame ( 10 ) and a brake unit ( 22 ) for braking said measuring wheel ( 4 ). A load cell ( 2 ) is disposed on the support frame ( 10 ) horizontal to a rotating shaft ( 19 ) of the measuring wheel ( 4 ) for measuring a tension yielded between the support frame ( 10 ) and the measuring wheel ( 4 ) by braking the measuring wheel ( 4 ), and a load cell ( 11 ) is disposed on the support frame ( 10 ) vertical to the rotating shaft ( 19 ) of the measuring wheel ( 4 ) for measuring a carrying weight loaded on the measuring wheel ( 4 ). The support frame ( 10 ) is arranged elevatably in the inside of a box-like casing ( 5 ).

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates to a measuring apparatus of sliding friction coefficient for vehicle running road surface and more particularly to a measuring apparatus for measuring a sliding friction coefficient for the purpose of establishing a traffic regulation to restrict the running speed of a vehicle running on snowy and/or frozen road surface as well as to make it compulsory to get the vehicle's wheels fitted with snow chains to prevent traffic accidents caused from the snowy and/or frozen road surface in the winter period.

[0003] 2. Prior Art

[0004] In the known measuring apparatus of this kind, there are such apparatus for measuring sliding friction coefficient of road surface as installed directly on the road surface, as coupled to and towed by a normal automobile, and as operated during an automobile's running with a measuring apparatus loaded on the automobile.

[0005] While the known apparatus as described above installed directly on the road surface is compact and convenient for transporting, it is necessary to make such a traffic restriction as obliging to interrupt traffic of vehicles and the like at the time of installing the apparatus and actually measuring, and consequently the congestion of traffic is created on the road especially where there is a lot of traffic of automobiles. The measuring apparatus towed by an automobile, on the other hand, can measure the friction coefficient during the automobile's running and is not required to make such restriction as traffic interruption at the time of measuring, but it is a problem that the size of apparatus is made comparatively larger, and that it requires a comparative large space for storage at the time not in use, as this is a type which is coupled to and towed by an automobile. Such the measuring apparatus loaded on the automobile has been developed to measure the sliding friction coefficient mainly for a rapid transmit high-way, and the automobile to load the measuring apparatus is limited to such a big size one as a large bus or truck, as the automobile has to run at a high speed and load the heavy weight of the measuring apparatus and consequently it is very expensive and uneconomical for manufacturing a vehicle suitable therefor or remodeling an existing vehicle properly.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to resolve the problems of the prior arts as described above and to provide a measuring apparatus of sliding friction coefficient which is extremely compact in construction and can be simply, easily and removably loaded on a compact automobile, and which can measure simply and accurately the sliding friction on the running road surface during an automobile's running, without interrupting traffic of vehicles such as automobiles.

[0007] A measuring apparatus of sliding friction coefficient for vehicle running road surface according to the present invention comprises a measuring wheel supported rotatably on a support frame and a brake unit for braking the measuring wheel, wherein a load cell is provided on the support frame placed in the running direction of the measuring wheel horizontally to a rotating shaft thereof for measuring a tension between the support frame and the measuring wheel occurred from the braking action applied to the measuring wheel, a load cell for measuring a carrying weight loaded on the measuring wheel is provided on the support frame vertically to the rotating shaft of the measuring wheel, and the support frame of the measuring wheel is disposed elevatably within a box-like casing which is removably loaded on a compact automobile.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is an elevation view showing the measuring apparatus of the present invention loaded on a vehicle;

[0009]FIG. 2 is an elevation view of the measuring apparatus according to the present invention; and

[0010]FIG. 3 is a side view of the measuring apparatus according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011]FIG. 1 shows a measuring apparatus 1 for measuring a sliding friction coefficient of the running road surface loaded on an automobile 2, said measuring apparatus 1 can be fixed on the floor chassis of the automobile 2 in such manner that a measuring wheel 4 can run in contact with the running road surface through an aperture 3 formed on the floor chassis of the automobile 2, and can be removed from the floor chassis of the automobile 2 for storage during non-use period outside of the winter period so that the automobile 2 can be used as a normal vehicle with the aperture 3 closed.

[0012] The measuring apparatus 1 includes a box-like casing 15 which is removably mounted on the floor chassis of the compact automobile 2, the casing 5 is opened at the bottom portion and is provided with an air cylinder 6 at the upper wall and with guide rails 7, 8 at the inside of the both side walls. A piston rod 9 of the air cylinder 6 is extended into the box-like casing 5 through an upper wall thereof and is fitted at the lower end to a support frame 10 disposed within the casing 5 via a load cell 11 for measuring a carrying weight to be loaded on the measuring wheel.

[0013] The support frame 10 comprises a horizontal plate 12 and a vertical plate 13 connected to one side of the horizontal plate 12, said horizontal plate 12 is provided at the other side with a slider 14 engaged with the guide rail 7 which is mounted on the box-like casing 5, said vertical plate 13 is arranged in the running direction of the running wheel 4, and is provided with sliders 15, 15 engaged to the guide rail 8 which is mounted on the box-like casing 5, and thus the support frame 10 can be moved elevatably within the box-like casing 5 along the guide rails 7, 8 by means of the piston rod 9 of the air cylinder 6.

[0014] The horizontal plate 12 of the support frame 10 is provided at the both side ends of the lower face thereof with flanges 16, 16 projected downwardly. A support rod 17 is mounted between the flanges 16, 16 and is extended vertically to the piston rod 9 in the lower side of the horizontal plate 12. Vertical arms 18, 18 are mounted pivotably on the support rod 17 and are extended downwardly in the both sides of the piston rod 9. The measuring wheel 4 is supported rotatably by a rotating shaft 19 between the lower ends of the two vertical arms 18, 18, to which one ends of horizontal arms 20, 20 extending horizontally to the running direction of the measuring wheel 4 is connected, and the other ends of the horizontal arms 20, 20 are connected to the lower end of the vertical plate 13 of the support frame 10 via a load cell 21 for measuring a tension occurred between the support plate 10 and the measuring wheel 4 by braking the measuring wheel 4.

[0015] A brake unit 22 is mounted on the vertical arm 18 of the support frame 10 for braking the measuring wheel 4, and said brake unit 22 is adapted so as to brake the measuring wheel 4 by actuating the air cylinder (not shown in the drawings) to pull a chain 23.

[0016] The vertical arms 18, 18 and horizontal arms 20, 20 constitutes the support frame 10 of the measuring wheel 4. As the load cell 11 is provided on the vertical arms 18, 18 extending vertically to the rotating shaft 19 of the measuring wheel 4, a carrying weight loaded on the measuring wheel 4 can be measured accurately by the load cell 11. As the load cell 21 is provided on the horizontal arms 20, 20 extending horizontally to the rotating shaft 19 of the measuring wheel 4, a tension yielded between the support frame 10 and the measuring wheel 4 by braking the measuring wheel 4 can be measured accurately by the load cell 21. The load cell 11 for measuring the carrying weight and the load cell 21 for measuring the tension constitute a pressure gauge for calculating the sliding friction coefficient which is connected to a recorder.

[0017] The measuring wheel 4 must be driven by means of the air cylinder 6 to touch to the road surface with optical load during the running thereon at constant speed of an automobile equipped with the measuring apparatus according to the present invention. When the automobile with the measuring wheel 4 is arrived at the measuring site of the snowy and/or frozen road surface, the measuring wheel is braked and stopped without changing the automobile's running speed, whereby the sliding friction is produced between the road surface and the measuring wheel 4 and then the tension corresponding to said sliding friction is yielded between the support frame 10 and the measuring wheel 4. At this time, the carrying load is measured by the load cell 11 on the one hand and the tension is measured by the load cell 21 on the other hand and then the friction coefficient can be obtained from the carrying load and tension load measured by two load cells 11, 21.

[0018] The measuring apparatus of sliding friction coefficient for vehicle running road surface according to the present invention is extremely simple and compact in construction, and is simply and easily loadable on a compact automobile. Further, it is possible for the measuring apparatus of the present invention to perform the most accurate measuring of the sliding friction coefficient of the snowy and/or frozen road surface under the running of automobile without causing any interruption of traffic of vehicle. Furthermore the measuring apparatus of the present invention is simply and easily removable from the automobile and is easy to store at the time not in use which the automobile can be used as normal vehicle. 

What is claimed is:
 1. A measuring apparatus of sliding friction coefficient for vehicle running road surface comprising a support frame, a measuring wheel supported rotatably in said supporting frame, a brake unit for braking said measuring wheel, a load cell for measuring a tension yielded between said support frame and said measuring wheel by braking said measuring wheel, a load cell for measuring a carrying weight loaded on said measuring wheel, and a box-like casing having said support frame elevatably arranged in the inside thereof.
 2. A measuring apparatus according to claim 1, wherein said box-like casing is provided at the upper wall with an air cylinder and at the opposite side walls with guide rails, a piston rod of said air cylinder is mounted via the load cell for measuring the carrying load to the support frame arranged in the inside of said box-like casing, said support frame is provided with sliders engaged to said guide rails, and said support frame is movable upwardly and downwardly along the guide rails by the means of the air cylinder.
 3. A measuring apparatus according to claim 1 or 2, wherein said support frame comprises a horizontal plate and a vertical plate connected to said horizontal plate, said horizontal plate has a support rod supported by flanges in the lower side, two vertical arms are mounted pivotably to said support rod and has the measuring wheel supported rotatably by a rotating shaft in the lower end, and horizontal arms are connected at their one ends to the lower ends of said vertical arms and are connected at their other ends to the vertical plate via the load cell for measuring the tension.
 4. A measuring apparatus according to claim 1 or 2 wherein the box-like casing is fixed removably on the floor chassis of a compact automobile in such manner that the measuring wheel can run in contact with the running road surface through an aperture formed in the floor chassis of the automobile. 